1. With scarcely a glance at the items, the clerk sweeps them across an aperture, where a special marking on each item is scanned by a low-powered laser beam inside the machine, connected to a remote computer.
    收款员几乎不看商品，只是把商品从机器上的孔眼处一扫而过，机器里的低能量激光对商品上的一个特殊标志进行扫描，这台扫描机与另一台电脑相联。

2. The light came through a narrow aperture.
    光线来自一个狭窄的隙缝。